gistfile1.rb

Ruby aws-sdk has poor documentation, and I wasn't able to locate it as well. Below is a function that I have created to check whether a file has read permission or not. Modify it as per your needs:

     def check_if_public_read(object)
        object.acl.grants.each do |grant|
          begin
            if(grant.grantee.uri == "http://acs.amazonaws.com/groups/global/AllUsers")
              return true if ([:read, :full_control].include?(grant.permission.name))
            end
          rescue
          end
        end
        return false
      end

where object is any S3 Object:

 

     AWS.config(
        :access_key_id     => "access key",
        :secret_access_key => "secret key"
      )
      s3 = AWS::S3.new
    
    file = s3.buckets["my_bucket"].objects["path/to/file.png"]
    
    check_if_public_read(file) => true